LA MISSION MSL
Mars Science Laboratory launch took place on November 26, 2011. The arrival took place on August 6, 2012. The planned primary launch period was chosen based on the availability of the Mars Reconnaissance Orbiter (MRO) and direct-to-Earth (DTE) entry, descent and landing communication strategies.
NASA's Kennedy Space Center in Florida, selected at the beginning of june 06, Lockheed Martin Commercial Launch Services Inc. to supply an Atlas V launcher for Curiosity. The ATLAS V launch vehicle has a 5-meters fairing. At launch, the spacecraft mass was around 3900 kilograms.
The cruise phase begun soon after separation from the launch vehicle when the spacecraft completed the launch phase. Cruise ended when the spacecraft was 45 days from entry into the martian atmosphere, when the approach phase begun.
Major activities during the cruise phase:
health checks and upkeeping of the spacecraft in its cruise configuration
monitoring and calibrating the spacecraft and sub-systems
attitude correction turns (spins to maintain the antenna pointing toward Earth for communications and the solar panels pointed toward the sun for power)
navigation activities, including trajectory correction maneuvers, for determining and correcting the vehicle's flight path and for training navigators prior to approach
preparation for entry, descent, and landing and surface operations, including communication tests used during entry, descent, and landing
To ensure a successful entry, descent, and landing, engineers begun intensive preparations during the approach phase, 45 days before the spacecraft entered the martian atmosphere. It lasted until the spacecraft entered the martian atmosphere, which extends 3500 kilometers as measured from the center of the red planet.
The activities that engineers typically focused on during the approach phase include:
the final trajectory correction maneuvers, which were used to make final adjustments to the spacecraft's incoming trajectory at Mars
attitude pointing updates, as necessary, for communications and power
frequent "Delta DOR" measurements that monitored the spacecraft's position and ensure accurate delivery
start of the entry, descent, and landing behavior software, which automatically executed commands during that phase
entry, descent, and landing parameter updates
spacecraft activities leading up to the final turn to the entry attitude and separation from the cruise stage
the loading of surface sequences and communication windows needed for the first several sols (a "sol" is a martian day).
Entry, Descent, and Landing
The entry, descent, and landing (EDL) phase begun when the spacecraft reached the martian atmosphere, about 125 kilometers above the surface, and ended with the rover safe and sound on the surface of Mars.
Entry, descent, and landing for the Mars Science Laboratory mission included a combination of technologies inherited from past NASA's Mars missions, as well as exciting new technologies. The sheer size of the rover Curiosity (900 kilograms) precluded it from taking advantage of an airbag-assisted landing. Instead, the MSL used the sky crane touchdown system, which was capable of delivering a much larger rover onto the surface. It placed the rover on its wheels, ready to begin its mission.
The new entry, descent and landing architecture, with its use of guided entry, allowed for more precision. Where the Mars Exploration Rovers could have landed anywhere within their respective 150 by 20 kilometers landing ellipses, Mars Science Laboratory landed within a 20-kilometer ellipse! This high-precision delivery opened up more areas of Mars for exploration and potentially allow scientists to "virtually" roam where they have not been able to before. The entry, descent and landing sequence broke down into four parts:
Guided Entry - The spacecraft was controlled by small rockets during descent through the martian atmosphere, toward the surface.
Parachute Descent - Like Viking, Pathfinder and the Mars Exploration Rovers, the Mars Science Laboratory was slowed by a large parachute.
Powered Descent - Again, rockets controlled the spacecraft's descent until the rover separated from its final delivery system, the sky crane.
Sky Crane - Like a large crane on Earth - the sky crane system lowered the rover to a "soft landing" - wheels down - on the surface of Mars.
Narrowing of Mars rover, Curiosity, landing site by Nasa
Credit: NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS
The surface operations phase covers the rover's time on Mars. After reaching the surface of the red planet, Curiosity is being designed to have a primary mission time of one martian year. That is, it would continue to operate for at least 687 Earth days, surviving at least one martian winter in the process. MSL was designed to have higher clearance and greater mobility than any previous rover sent to Mars, traveling a distance of 5 to 20 kilometers from its landing site. While exploring Mars, the rover will collect, grind, distribute, and analyze approximately 70 samples of soil and rock.